Question

please solve this one........​

Answer 1

Since the rectangular surface level is increased,

 we can calculated the volume of earth dug and added on the rectangular plot.

Volume of earth dug = 240m x 180m x 0.25m

= 10800 m3

 This volume is also the volume of the drainlet

.= 2(240m x 10m x d m) + 2(180m x 10m x d m) 

= 10800 m3.d

= depth = 1.29 m

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